This invention relates to dispersible silicone compositions. More particularly, this invention relates to dispersible silicone compositions comprising a blend of a silicone composition and mineral oil.
The use of various silicone containing compositions as antifoams or defoamers is known. In this regard, it is well established that this art is highly unpredictable and slight modification can greatly alter performance of such compositions. Most of these compositions contain silicone fluid (usually dimethylpolysiloxane), often in combination with small amounts of silica filler. Additionally, these compositions may include various surfactants and dispersing agents in order to impart improved foam control or stability properties to the compositions.
Silicone compositions which are useful as foam control agents have been taught in the art. For example, Aizawa et al., in U.S. Pat. Nos. 4,639,489 and 4,749,740, the disclosures of which are hereby incorporated by reference, teach a method for producing a silicone defoamer composition wherein a complex mixture of polyorganosiloxanes, filler, a resinous siloxane and a catalyst to promote reaction of the other components are heated together at 50.degree. C. to 300.degree. C.
More recently, a method for preparing a composition similar to that described by Aizawa et al., cited supra, was disclosed by Miura in U.S. Pat. No. 5,283,004, the disclosure of which is hereby incorporated by reference. In this disclosure, the above mentioned complex silicone mixture additionally contains at least 0.2 weight parts of an organic compound having at least one group selected from --COR, --COOR' or --(OR").sub.n --, wherein R and R' are hydrogen or a monovalent hydrocarbon group, R" is a divalent hydrocarbon group having 2 to 6 carbon atoms and the average value of n is greater than one. It is further disclosed that all the ingredients, including a catalyst, must be reacted at elevated temperatures to obtain the desired antifoam agent.
John et al., in European Patent Application No. 217,501, published Apr. 8, 1987, discloses a foam control composition which gives improved performance in high foaming detergent compositions which comprises (A) a liquid siloxane having a viscosity at 25.degree. C. of at least 7.times.10.sup.-3 m.sup.2 /s and which was obtained by mixing and heating a triorganosiloxane-endblocked polydiorganosiloxane, a polydiorganosiloxane having at least one terminal silanol group and an organosiloxane resin, comprising monovalent and tetravalent siloxy units and having at least one silanol group per molecule, and (B) a finely divided filler having its surface made hydrophobic. John et al. further describes a method for making the foam control compositions and detergent compositions containing said foam control compositions.
Starch, in U.S. Pat. No. 4,983,316 discloses a dispersible antifoam composition for providing controlled foaming liquid laundry detergent formulations and wherein there is provided a non-aqueous emulsion of primary and secondary silicone antifoam agents, at least one nonionic silicone surfactant for emulsifying the primary and secondary antifoaming agents in a solvent, a first organic surfactant dispersing agent for assisting in dispersing the emulsified primary and secondary antifoaming agents in the liquid laundry detergents, and a second dispersing agent of a nonionic difunctional block-copolymer terminating in primary hydroxyl groups for further assisting in dispersing the emulsified primary and secondary antifoam agents in the liquid laundry detergent. A liquid laundry detergent composition containing the composition described immediately above is also disclosed. Starch, in U.S. Pat. No. 4,978,471 discloses a composition which contains essentially the same components as in the '316 patent, however in the '471 patent the secondary antifoam agent is a blend of a polydimethylsiloxane substituted with polar groups and a polydimethylsiloxane fluid.
Terae et al., in U.S. Pat. No. 4,690,713, discloses an antifoam composition comprising (a) 100 parts by weight of a hydrocarbon oil, such as a spindle oil or silicone fluid (e.g. a polydimethylsiloxane fluid having a viscosity of 20 to 1,000,000 centistokes at 25.degree. C., (b) 0.1 to 40 parts by weight of an organosilane compound having 1 to 3 hydroxy groups or hydrolyzable groups (such as alkoxy, acyloxy, and alkenyloxy groups), (c) 1 to 40 parts by weight of a finely divided silica powder and optionally a catalyst.
Foam control compositions which contain mineral oil have also been disclosed. For example, in Great Britain Patent Specification No. 1224026 is disclosed a process for inhibiting or destroying foam in an aqueous system which comprises adding to the aqueous system an antifoaming agent which is composed of (A) 10 parts by weight of a water insoluble organic liquid which can be a mineral oil and (B) from 0.1 to 5.0 parts by weight of an organopolysiloxane which is compatible in (A) consisting essentially of (1) SiO.sub.2 units and (2) R.sub.3 SiO.sub.1/2 units in which R is a monovalent hydrocarbon radical containing from 1 to 6 inclusive carbon atoms, and in which the ratio of (1) units to (2) units is within the range from 0.6/1 to 1.2/1.
Keil, in U.S. Pat. No. 3,666,681 discloses an antifoaming agent for aqueous systems consisting essentially of a mixture of (A) 100 parts by weight of a water insoluble organic liquid or solid which can be a mineral oil, (B) from 0.5 to 10 parts by weight of an organopolysiloxane compound selected from the group consisting of a hydroxyl terminated dimethylpolysiloxane fluid having a viscosity of at least 35 centistokes at 25.degree. C. and a benzene soluble organopolysiloxane resin comprising (1) R.sub.3 SiO.sub.1/2 units and (2) SiO.sub.2 units in which R is a monovalent hydrocarbon radical containing from 1 to 6 carbon atoms inclusive, and in which the ratio of (1) units to (2) units is from 0.6:1 to 1.2:1, (C)/from 0.5 to 10 parts by weight of a filler such as finely divided silica, (D) from 0.002 to 5 parts by weight of a compound which is a hydrocarbon amine, ammonia, a disilazane, or a compound of the formula R'OH in which R' is an alkali of alkaline earth metal.
Great Britain Patent Specification No. 1496011 discloses a composition suitable for use in an oil-based defoamer consisting essentially of (1) from 55 to 96 percent by weight of a siloxane having the unit formula CH.sub.3 Si(OCH.sub.3).sub.x O.sub.3-x/2 in which x is such that there is from 10 to 35 percent by weight of methoxy groups based on the weight of (1), (2) from 2 to 25 percent by weight of a hydrocarbon solvent soluble copolymer of (CH.sub.3).sub.3 SiO.sub.1/2 units and SiO.sub.2 units in which the ratio of (CH.sub.3).sub.3 SiO.sub.1/2 units to SiO.sub.2 units is in the range of 0.5/1 to 1.2/1, and (3) from 2 to 25 percent by weight of a silicon-bonded hydroxyl terminated methylpolysiloxane fluid. This reference further discloses a defoaming composition for aqueous systems comprising a composition prepared by mixing (A) 100 parts by weight of a mineral oil, (B) 3 to 20 parts by weight of the above composition, and (C) a condensation catalyst for (B), and thereafter heating the mixture at a temperature of at least 50.degree. C. unit an effective defoamer is obtained.
Rauline in U.S. Pat. No. 4,564,467 discloses an oil composition comprising an oil having a kinematic viscosity of 5 to 30 centistokes at 25.degree. C., and a long-chain alkyl organosiloxane.